Virtual Axle Temperature Estimation via Convection Models

Solution Overview

Problem

Conventional drivetrains lack real-time monitoring of axle assembly temperatures, leading to potential overheating during high load situations, which can cause damage and increase warranty costs, and existing solutions like physical sensors are costly.

Innovation Solution

A real-time virtual axle assembly temperature sensor system that uses a lumped system model and convection heat transfer models to estimate axle assembly temperatures based on ambient and transmission fluid temperatures, operating mode, and other parameters, allowing for torque management and speed limiting.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If physical temperature sensors are installed in the axle assembly, then real-time temperature monitoring is achieved, but system cost increases

Engineering Contradiction:

Improveaxle assembly temperature monitoringVSAvoidsensor installation

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent creates a virtual copy of the temperature sensor by implementing a computational model that calculates axle assembly temperature based on input shaft temperature, transmission fluid temperature, and operating conditions. This virtual sensor replaces the need for physical temperature sensors within the axle assembly, maintaining monitoring capability while eliminating the cost and complexity of physical sensor installation.

Inventive Principle:

Principle #26Copying

Solution Approach 2:

The patent substitutes the mechanical/physical temperature sensing system with an electronic computational system. Instead of using physical sensors to directly measure temperature, the system uses a controller to calculate temperature based on mathematical models and input from existing temperature sensors (input shaft and transmission fluid), thereby replacing the need for complex physical sensor infrastructure.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If physical temperature sensors are installed in the axle assembly, then overheating detection is improved, but manufacturing cost increases

Engineering Contradiction:

Improveoverheating detectionVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent creates a virtual copy of the temperature sensor by implementing a computational model that calculates axle assembly temperature based on input shaft temperature, transmission fluid temperature, and operating conditions. This virtual sensor replaces the need for physical temperature sensors within the axle assembly, maintaining monitoring capability while eliminating the cost and complexity of physical sensor installation.

Inventive Principle:

Principle #26Copying

3Device complexity

If axle assembly temperature is not monitored, then system simplicity is maintained, but potential damage from overheating occurs

Engineering Contradiction:

Improvesystem simplicityVSAvoidoverheating damage

Core Design Contradiction:

Device complexityVSObject-affected harmful factors

Solution Approach 1:

The patent substitutes the mechanical/physical temperature sensing system with an electronic computational system. Instead of using physical sensors to directly measure temperature, the system uses a controller to calculate temperature based on mathematical models and input from existing temperature sensors (input shaft and transmission fluid), thereby replacing the need for complex physical sensor infrastructure.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent implements a feedback mechanism where the controller continuously calculates axle assembly temperature based on operating conditions and compares it against threshold values. When overheating is detected, the system can trigger warnings or adjust operation, creating a closed-loop protection system that prevents damage while maintaining simplicity.

Inventive Principle:

Principle #23Feedback

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables effective prevention of axle assembly overheating by estimating temperatures accurately without the need for physical sensors, reducing costs and preventing damage, while also optimizing lubricant usage and vehicle performance.

Implementation Method 1

the heat lost to the environment via the gearbox housing and the axle shaft housing is determined based on a natural convection heat transfer model when the vehicle is non-moving

Methodology Applied

Scientific EffectNatural convection: Free Convection

Implementation Method 2

the heat lost to the environment via the gearbox housing and the axle shaft housing is determined based on a forced convection heat transfer model when the vehicle is moving

Methodology Applied

Scientific EffectForced convection: Forced Convection

Data Source

PatentUS9714871B2Real-time virtual axle assembly temperature sensor

Publication Date: 2017.07.25 FCA US LLC

AI summary

Techniques for real-time virtual sensing of an axle assembly temperature include determining, at a controller of a vehicle, an initial temperature of an axle assembly of the vehicle based on an ambient temperature and a fluid temperature of a transmission. The techniques include determining, at the controller, an operating mode of the vehicle, the operating mode of the vehicle being one of moving and non-moving. The techniques also include estimating, at the controller, a temperature of the axle assembly based on the initial axle assembly temperature and the vehicle operating mode using an axle temperature model.